include/linux/linkage.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_LINKAGE_H
   3 #define _LINUX_LINKAGE_H
   4
   5 #include <linux/compiler_types.h>
   6 #include <linux/stringify.h>
   7 #include <linux/export.h>
   8 #include <asm/linkage.h>
   9
  10 /* Some toolchains use other characters (e.g. '`') to mark new line in macro */
  11 #ifndef ASM_NL
  12 #define ASM_NL           ;
  13 #endif
  14
  15 #ifdef __cplusplus
  16 #define CPP_ASMLINKAGE extern "C"
  17 #else
  18 #define CPP_ASMLINKAGE
  19 #endif
  20
  21 #ifndef asmlinkage
  22 #define asmlinkage CPP_ASMLINKAGE
  23 #endif
  24
  25 #ifndef cond_syscall
  26 #define cond_syscall(x) asm(                            \
  27         ".weak " __stringify(x) "\n\t"                  \
  28         ".set  " __stringify(x) ","                     \
  29                  __stringify(sys_ni_syscall))
  30 #endif
  31
  32 #ifndef SYSCALL_ALIAS
  33 #define SYSCALL_ALIAS(alias, name) asm(                 \
  34         ".globl " __stringify(alias) "\n\t"             \
  35         ".set   " __stringify(alias) ","                \
  36                   __stringify(name))
  37 #endif
  38
  39 #define __page_aligned_data     __section(.data..page_aligned) __aligned(PAGE_SIZE)
  40 #define __page_aligned_bss      __section(.bss..page_aligned) __aligned(PAGE_SIZE)
  41
  42 /*
  43  * For assembly routines.
  44  *
  45  * Note when using these that you must specify the appropriate
  46  * alignment directives yourself
  47  */
  48 #define __PAGE_ALIGNED_DATA     .section ".data..page_aligned", "aw"
  49 #define __PAGE_ALIGNED_BSS      .section ".bss..page_aligned", "aw"
  50
  51 /*
  52  * This is used by architectures to keep arguments on the stack
  53  * untouched by the compiler by keeping them live until the end.
  54  * The argument stack may be owned by the assembly-language
  55  * caller, not the callee, and gcc doesn't always understand
  56  * that.
  57  *
  58  * We have the return value, and a maximum of six arguments.
  59  *
  60  * This should always be followed by a "return ret" for the
  61  * protection to work (ie no more work that the compiler might
  62  * end up needing stack temporaries for).
  63  */
  64 /* Assembly files may be compiled with -traditional .. */
  65 #ifndef __ASSEMBLY__
  66 #ifndef asmlinkage_protect
  67 # define asmlinkage_protect(n, ret, args...)    do { } while (0)
  68 #endif
  69 #endif
  70
  71 #ifndef __ALIGN
  72 #define __ALIGN         .align 4,0x90
  73 #define __ALIGN_STR     ".align 4,0x90"
  74 #endif
  75
  76 #ifdef __ASSEMBLY__
  77
  78 #ifndef LINKER_SCRIPT
  79 #define ALIGN __ALIGN
  80 #define ALIGN_STR __ALIGN_STR
  81
  82 #ifndef GLOBAL
  83 #define GLOBAL(name) \
  84         .globl name ASM_NL \
  85         name:
  86 #endif
  87
  88 #ifndef ENTRY
  89 #define ENTRY(name) \
  90         .globl name ASM_NL \
  91         ALIGN ASM_NL \
  92         name:
  93 #endif
  94 #endif /* LINKER_SCRIPT */
  95
  96 #ifndef WEAK
  97 #define WEAK(name)         \
  98         .weak name ASM_NL   \
  99         ALIGN ASM_NL \
 100         name:
 101 #endif
 102
 103 #ifndef END
 104 #define END(name) \
 105         .size name, .-name
 106 #endif
 107
 108 /* If symbol 'name' is treated as a subroutine (gets called, and returns)
 109  * then please use ENDPROC to mark 'name' as STT_FUNC for the benefit of
 110  * static analysis tools such as stack depth analyzer.
 111  */
 112 #ifndef ENDPROC
 113 #define ENDPROC(name) \
 114         .type name, @function ASM_NL \
 115         END(name)
 116 #endif
 117
 118 #endif
 119
 120 #endif